1. Field of the Invention
This invention is in the field of bundling ties for securing together a plurality of electric wires, cables, tubes, etc.
2. Description of the Prior Art
A wide variety of bunding ties have been fabricated. Many of these are described in the patent literature, among which are the following.
A binding clip having an elongated flexible tongue integrally attached to a rigid head which has an elongated eye containing a pawl flexibly joined to the end of the head outermost with respect to the tongue is described in U.S. Pat. No. 3,486,201 issued to Bourne. The eye in this clip is a straight passage of uniform cross section complementary to that of the tongue. Ratchet teeth on the pawl project into the eye parallel to its major dimension, and these teeth are intended to engage teeth medially positioned upon the tongue. The tongue is wider than the pawl and contains plain marginal portions outside of the teeth; these plain marginal portions abut rigid parts of the head in an attempt to insure effective interengagement of the complementary teeth so that return movement of the tongue is resisted.
Feldberg, in U.S. Pat. No. 3,588,962, describes a plastic bundling strap wherein a pawl is integral with a head and is formed so that it moves relative to the head because only a narrow neck is used to attach the pawl to the head. This facilitates flexing of the pawl during insertion of the strap. One side of this pawl is formed as a surface of a narrow slot, and the pawl swings away from the opposed surface of the slot as the strap is moved into the locking slot of the head. Thus, the pawl flexes back and forth to allow the ratchet teeth of the strap to move past the pawl. However, the opposed surface acts as a stop against free reverse swinging of the pawl to prevent withdrawal of the strap once it has been tightened into position.
Caveney, in U.S. Pat. No. 3,660,869, discloses another tie which has an elongated flexible strap with a row of teeth thereon and a frame integral with one end of the strap. A ledge is provided on an end wall of the head opening and a pawl is pivotally mounted on and integral with the ledge.
Despite the fact that many different cable ties have been heretofore proposed, none has proven entirely satisfactory to date. This is partially evidenced, for example, by the large number of patents directed to new cable tie designs, including many recently issued patents. While it may not be initially apparent why prior ties have not been satisfactory, a more detailed analysis indicates that many of the design features required for effective locking, particularly for both large and small bundle diameters, are contrary to those design features necessary for efficient fabrication of the ties.